1. Clinical Burkholderia pseudomallei isolates from north Queensland carry diverse bimABm genes that are associated with central nervous system disease and are phylogenomically distinct from other Australian strains.
- Author
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Burnard, Delaney, Bauer, Michelle J., Falconer, Caitlin, Gassiep, Ian, Norton, Robert E., Paterson, David L., and Harris, Patrick NA
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MELIOIDOSIS , *BURKHOLDERIA pseudomallei , *CENTRAL nervous system diseases , *GENOMICS , *COMPARATIVE genomics ,CENTRAL nervous system infections - Abstract
Background: Burkholderia pseudomallei is an environmental gram-negative bacterium that causes the disease melioidosis and is endemic in many countries of the Asia-Pacific region. In Australia, the mortality rate remains high at approximately 10%, despite curative antibiotic treatment being available. The bacterium is almost exclusively found in the endemic region, which spans the tropical Northern Territory and North Queensland, with clusters occasionally present in more temperate climates. Despite being endemic to North Queensland, these infections remain understudied compared to those of the Northern Territory. Methodology/Principal findings: This study aimed to assess the prevalence of central nervous system (CNS) disease associated variant bimABm, identify circulating antimicrobial resistance mutations and genetically distinct strains from Queensland, via comparative genomics. From 76 clinical isolates, we identified the bimABm variant in 20 (26.3%) isolates and in 9 (45%) of the isolates with documented CNS infection (n = 18). Explorative analysis suggests a significant association between isolates carrying the bimABm variant and CNS disease (OR 2.8, 95% CI 1.3–6.0, P = 0.009) compared with isolates carrying the wildtype bimABp. Furthermore, 50% of isolates were identified as novel multi-locus sequence types, while the bimABm variant was more commonly identified in isolates with novel sequence types, compared to those with previously described. Additionally, mutations associated with acquired antimicrobial resistance were only identified in 14.5% of all genomes. Conclusions/Significance: The findings of this research have provided clinically relevant genomic data of B. pseudomallei in Queensland and suggest that the bimABm variant may enable risk stratification for the development CNS complications and be a potential therapeutic target. Author summary: Melioidosis is a life-threatening infection, caused by the Gram-negative bacterium Burkholderia pseudomallei, which is endemic to tropical regions in Australia. Variants of the bimA gene have been proposed as a virulence factor associated with more severe disease. In a genomic analysis of 76 clinical B. pseudomallei isolates from Queensland, Australia, we identified that the bimABm variant was associated with infection involving the central nervous system (odds ratio 2.8, 95% Confidence Interval: 1.3–6.0, P = 0.009), compared to isolates with the wild-type allele bimABp. Half of the isolates from this region were novel multi-locus sequence types, and bimABm was more commonly seen in these novel sequence types. Early genomic characterisation to identify virulence factors such as bimABm, may be useful as an early marker of more complex disease that could guide further investigation and help determine optimal treatment. Further investigation of a "genomics-guided" approach to the clinical management of this complex infectious disease are warranted. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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